Thread

1993.12.08 21:25 "Re: CMYK Tiff Question", by Dan Seyb

Our new Scanner can only write CMYK Tiff files - BUT we need to have some RGB format.

I know it is only a (close) guess to convert from CMYK to RGB. Did someone out there ever write a little tool that would do the job. I have the libtiff (v3.3beta) but do not necessarily want
to work my way into it as I'm more interested in the images.

Could someone help please...

The conversion simple enough i doubt anyone would bother unless it is part of a larger package. The Utah Raster Toolkit is the only place i can think to look for something like that.

The conversion is:

R = 1 - C G = 1 - M B = 1 - Y

if C == M == Y == 0, R = G = B = 1 - K

The only place that might get tricky would be if the scanner
does undercolor removal (C, M, or Y != 0 and K != 0), and that
would be a smart scanner.

And a hint:

Track down Foley, van Dam, Feiner & Hughes "Computer Graphics, Principles and Practice, second edition", Addison-Wesley Publishing. It should be available at any decent
technical/engineering bookstore. That is the bible.